module.register() in the prerender loader prints DEP0205 on Node 26 #34358

Command

build

Is this a regression?

• Yes, this behavior used to work in the previous version

The previous version in which this bug was not present was

No response

Description

@angular/build registers its in-memory ESM loader with module.register(), which Node runtime-deprecated in Node 26. The call is in src/utils/server-rendering/esm-in-memory-loader/register-hooks.js:

register('./loader-hooks.js', { parentURL: pathToFileURL(__filename), data: workerData });

esm-in-memory-loader/utils.js points IMPORT_EXEC_ARGV at that file, and server-rendering/prerender.js passes it as the execArgv of every prerender worker, so each worker prints DEP0205 to stderr during ng build.

Node runtime-deprecated the API in nodejs/node#62401, merged 2026-04-01 and labelled semver-major, so the warning starts at Node 26. @angular/build 22.2.2 declares engines.node as ^22.22.3 || ^24.15.0 || >=26.0.0, so this is a supported Node version.

This is not an Angular regression, the code did not change, Node did.

Minimal Reproduction

Any app with prerendering, built on Node 26:

1. ng new repro --ssr and keep prerendering enabled.
2. ng build on Node 26.
3. DEP0205 appears on stderr, once per prerender worker.

Measured on our app with Angular CLI 22.2.2, @angular/build 22.2.2, Node 26.5.0 on Windows, and on our CI agent (Linux, Node 26) in the production build step.

Also reproduced without a build, which isolates the loader from the rest of the pipeline. A worker created the way prerender.js creates one:

const { Worker } = require('node:worker_threads');
const { IMPORT_EXEC_ARGV } = require('@angular/build/src/utils/server-rendering/esm-in-memory-loader/utils.js');
new Worker('./stay-alive.cjs', {
  execArgv: [IMPORT_EXEC_ARGV],
  workerData: { outputFiles: {}, workspaceRoot: process.cwd() },
});

with stay-alive.cjs holding the worker open for a moment (setTimeout(() => {}, 700)). Without the flag it prints DEP0205 in 3 of 3 runs, with NODE_OPTIONS=--disable-warning=DEP0205 it is clean in 3 of 3 runs.

Worth knowing when reproducing: DEP0205 is emitted asynchronously, so a worker whose body is process.exit(0) exits before the warning flushes and the run looks clean.

Exception or Error

(node:24372) [DEP0205] DeprecationWarning: `module.register()` is deprecated. Use `module.registerHooks()` instead.
(Use `node --trace-deprecation ...` to show where the warning was created)

Your Environment

Angular CLI       : 22.2.2
Angular           : 22.2.1
Node.js           : 26.5.0
Package Manager   : pnpm 12.3.1
Operating System  : win32 x64

@angular-devkit/build-angular   22.2.2
@angular-devkit/core            22.2.2
@angular-devkit/schematics      22.2.2
@angular/build                  22.2.2
@angular/cli                    22.2.2
@angular/core                   22.2.1
@angular/platform-server        22.2.1
@angular/ssr                    22.2.2
rxjs                            7.8.2
typescript                      6.0.3
zone.js                         0.16.3

Anything else relevant?

A possible fix, from reading the two hook files. module.registerHooks() takes synchronous hooks, and loader-hooks.js is almost there already: initialize and resolve are synchronous, and load has exactly one await, await readFile(filePath), which readFileSync covers. The data: workerData channel is not needed either, because the hooks already run inside a worker that can read workerData directly.

The one real difference to weigh is that registerHooks runs the hooks on the calling thread rather than on a separate loader thread, so the synchronous read would block it.

The same Node 26 warning reported elsewhere, in case it helps: payloadcms/payload#18361 and Julien-R44/hot-hook#18.

What we do meanwhile: NODE_OPTIONS=--disable-warning=DEP0205 on the build step, which silences only this code.